Automotive engine control method

ABSTRACT

An engine control method for an automotive vehicle includes the steps of gathering and analyzing vehicle condition parameters from a vehicle condition detecting means, determining whether a signal from a TCU is a shift signal or not, converting a throttle opening versus vehicle speed shift line into a engine torque versus vehicle speed shift line, and if the signal from the TCU is a shift signal, determining if a present acceleration pedal displacement value relative to the engine torque is less than a predetermined value, and synchronizing the engine torque to a predetermined value if the acceleration pedal displacement value indicates the engine torque is less than the predetermined value.

BACKGROUND OF THE INVENTION

[0001] (a) Field of the Invention

[0002] The present invention relates to an automotive engine controlmethod and, more particularly, to an engine control method for anautomatic transmission vehicle equipped with an electric throttlecontrol (ETC) device for reducing shift shocks, in which engine torqueof each speed range relative to the acceleration pedal displacement iscalculated and the throttle is adjusted such that the engine torque isguided by a formulated line.

[0003] (b) Description of the Related Art

[0004] Typically, an automatic transmission vehicle equipped with an ETCdevice performs a speed range shift control by a shift patternpredetermined in accordance with vehicle speed and throttle opening.

[0005] In this case, to reduce shift impact generated during a speedrange shift, shift control means sends a combined control signal to anengine control means so as to degrade engine torque.

[0006] However, this engine control mechanism has drawbacks in thatvalue of engine torque is calculated at every shift range forcompensating a torque displacement during the shift operation, and theengine torque reduction according to the combination controldeteriorates engine performance and fuel consumption.

SUMMARY OF THE INVENTION

[0007] The present invention has been made in an effort to solve theabove problems of the prior art.

[0008] It is an object of the present invention to provide an enginecontrol method for an automatic transmission vehicle equipped with anelectric throttle control (ETC) device for reducing shift shocks, inwhich engine torque of each speed range relative to the accelerationpedal displacement is calculated and the throttle opening is adjustedsuch that the engine torque is guided along the formulated line duringspeed range shift.

[0009] To achieve the above object, the engine control method for anautomotive vehicle of the present invention comprises the steps ofgathering and analyzing vehicle condition parameters from a vehiclecondition detecting means, determining whether a signal from a TCU is ashift signal or not, converting a throttle opening versus vehicle speedshift line into an engine torque versus vehicle speed shift line, and ifthe signal from the TCU is a shift signal, determining if a presentacceleration pedal displacement value relative to the engine torque isless than a predetermined value, and synchronizing the engine torque toa predetermined value if the acceleration pedal displacement valueindicates the engine torque is less than the predetermined value.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings, which are incorporated in andconstitute a part of the specification, illustrate an embodiment of theinvention, and, together with the description, serve to explain theprinciples of the invention:

[0011]FIG. 1 is a block diagram of an automotive engine control deviceaccording to a preferred embodiment of the present invention;

[0012]FIG. 2 is a flowchart showing an automotive engine control methodaccording to the preferred embodiment of the present invention;

[0013]FIG. 3a is a graph showing throttle opening variation according toacceleration pedal displacement in the automotive engine control methodof FIG. 2; and

[0014]FIG. 3b is a graph showing engine torque variation according toacceleration pedal displacement in the automotive engine control methodof FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] A preferred embodiment of the present invention will be describedhereinafter with reference to the accompanying drawings.

[0016] As shown in FIG. 1, an automotive engine control device comprisesvehicle condition detecting means 10 including an acceleration pedaldisplacement sensor 11, a vehicle speed sensor 12, a coolant temperaturesensor 13, and an engine rpm sensor 14; engine control means 20receiving vehicle condition signals from the vehicle condition detectingmeans 10, setting engine torque corresponding to each speed rangeaccording to the acceleration pedal displacement if the condition signalis a shift signal, producing a control signal for varying the throttleopening to an upshift opening according to a acceleration pedaldisplacement if the condition shift signal is an upshift signal, andproducing a shift permission signal; a transmission control means (TCU)30 for producing and sending a shift signal to the engine control means20 if shift control is determined, and producing and sending a controlsignal for shifting the speed range to a target speed range if receivinga shift signal from the engine control means 10; a throttle actuator 40for adjusting the throttle opening level on the basis of the controlsignal from the engine control means 20; an ignition device 50 foradjusting the ignition timing on the basis of the control signal fromthe engine control means 20; and a shift operation actuator 60 forsynchronizing a speed range to a target speed range on the basis of thecontrol signal from the shift control means 30.

[0017] The automotive engine control method of the above structuredengine control device will be described hereinafter with reference toFIG. 2, FIG. 3a, and FIG. 3b.

[0018] In the automatic transmission vehicle of the present invention,the shift line formed as a vehicle speed versus throttle openingfunction is converted into a vehicle speed versus engine torque linesuch that the continuous throttle opening value is mapped to thecontinuous engine torque value in the same shift line. Accordingly, thethrottle opening is determined by the engine torque relative to theacceleration pedal displacement.

[0019] The continuous throttle opening at each speed range is measuredand recorded in a memory, and a point where the driving torque TOQ isnot changing regardless of the acceleration pedal displacement increaseis set as a value POS_SAT.

[0020] After the driving torque TOQ is fixed at POS_SAT, engine torquevalues are measured at each speed range so as to be recorded as mappingvalues TOQ_STs and a correlation between the acceleration pedaldisplacement and the engine torque is calculated and recorded.

[0021] All the values measured through several sequences are set in amemory of the engine control means 20.

[0022] During engine operation, the engine control means 20 with apreset engine control program produces and sends a signal to the vehiclecondition detecting means 10 and then the vehicle condition detectingmeans 10 responsively sends back a response signal on the basis ofparameters from the acceleration pedal displacement, vehicle speed,coolant temperature, and engine rpm detected by the acceleration pedaldisplacement sensor 11, vehicle speed sensor 12, coolant temperaturesensor 13, and engine rpm sensor 14 in step S100.

[0023] After receiving the response signal from the vehicle conditiondetecting means 10, the engine control means 20 analyzes the responsesignal and records the same in the memory, and if receiving a signalfrom the TCU 30, the engine control means 20 determines whether thesignal from the TCU 30 is a shift signal or not in step S110.

[0024] If the signal from the TCU 30 is a shift signal, the enginecontrol means 20 maps the engine torque relative to the accelerationpedal displacement at respective speed ranges to the preset values instep S120 (see FIG. 3a).

[0025] After the mapping is complete, the engine control means 20determines whether the shift signal is an upshift signal or not in stepS130.

[0026] If the shift signal from the TCU 30 is the upshift signal, theengine control means 20 determines if the acceleration pedaldisplacement value detected by the acceleration pedal displacementsensor 11 of the vehicle condition detecting means 10 is less than thevalue POS_SAT in step 140.

[0027] If the acceleration pedal value is less than POS_SAT, the enginecontrol means 20 converts the throttle opening of the first forwardspeed into the throttle opening of the second forward speed and thensends a throttle opening signal to the throttle actuator 40 in stepS150.

[0028] The throttle actuator 40 is operated in accordance with thethrottle opening signal from the engine control means 20 so as to adjustthe throttle opening.

[0029] Consequently, the engine control means 20 sends an upshiftpermission signal to the TCU 30 and returns to a main routine in stepS160.

[0030] The TCU 30 produces and sends a shift control signal to the shiftactuator 60 for shifting up the shift range on the basis of the upshiftpermission signal from the engine control means 20.

[0031] The shift actuator 60 is operated according to the shift controlsignal from the TCU 30 such that the first speed range is converted intothe second speed range.

[0032] However, if the acceleration pedal displacement value is not lessthan the value POS_SAT, the engine control means 20 determines that theengine torque is greater than a required torque at the correspondingspeed range, so it produces and sends a ignition control signal to theignition device 50 according to the preset mapping table (TOQ_ST) instep S170 to reduce engine torque, and subsequently sends an upshiftpermission signal to the TCU 30 in step S160.

[0033] As described above, in the engine control method of the presentinvention, engine torque at each speed range relative to theacceleration pedal displacement is calculated and the throttle openingis adjusted such that the engine torque is guided by the formulated linewhile shifting speed range, resulting in a reduction of shift shock.

[0034] While this invention has been described in connection with whatis presently considered to be the most practical and preferredembodiment, it is to be understood that the invention is not limited tothe disclosed embodiments, but, on the contrary, is intended to covervarious modifications and equivalent arrangements included within thespirit and scope of the appended claims.

What is claimed is:
 1. An engine control method for an automotivevehicle comprising the steps of: gathering and analyzing vehiclecondition parameters from a vehicle condition detecting means;determining whether a signal from a TCU is a shift signal or not;converting a throttle opening versus vehicle speed shift line into anengine torque versus vehicle speed shift line, if the signal from theTCU is a shift signal; determining if a present acceleration pedaldisplacement value relative to the engine torque is less than apredetermined value; and synchronizing the engine torque to apredetermined value if the acceleration pedal displacement valueindicates the engine torque is less than the predetermined value.
 2. Anengine control method of claim 1 wherein if the present accelerationpedal displacement value is greater than the predetermined value, anengine torque reduction signal is produced by an engine control means.3. An engine control device for an automotive vehicle comprises: vehiclecondition detecting means for detecting vehicle conditions such asacceleration pedal displacement, vehicle speed, a coolant temperature,and engine rpm; engine control means which receives vehicle conditionsignals from the vehicle condition detecting means, sets engine torquecorresponding to each speed range according to the acceleration pedaldisplacement if the condition signal is a shift signal, producing acontrol signal for varying the throttle opening to an upshift openingaccording to a acceleration pedal displacement if the condition shiftsignal is an upshift signal, and producing a shift permission signal;transmission control means for producing and sending a shift signal tothe engine control means if shift control is determined, and producingand sending a control signal for shifting the speed range to a targetspeed range if receiving a shift signal from the engine control means; athrottle actuator for adjusting the throttle opening level on the basisof the control signal from the engine control means; an ignition devicefor adjusting the ignition timing on the basis of the control signalfrom the engine control means; and a shift operation actuator forsynchronizing a speed range to a target speed range on the basis of thecontrol signal from the shift control means.